The present invention relates to a new and improved method of, and device for, performing a start spinning operation entailing starting or recommencing spinning of a yarn or the like in a friction spinning apparatus.
Generally speaking, the method for performing a start spinning operation, meaning starting or recommencing spinning of a yarn or the like in a friction spinning apparatus, is of the type wherein free floating fibers are delivered in a fiber infeed or transport duct to a friction spinning surface of friction spinning means and conveyed on such friction spinning surface to a yarn formation position or location from which a yarn is withdrawn by yarn draw-off means, typically yarn draw-off rolls, during the yarn spinning operation.
The device for performing a start spinning operation is of the type which generally comprises a first friction spinning means having a friction spinning surface provided thereon to which there are delivered fibers. These fibers are formed into a twisted fiber structure or coil at a yarn formation position or location during performance of the yarn spinning operation. This twisted fiber structure or coil is withdrawn by a pair of yarn draw-off or withdrawal rolls, at least one roll of which is not continuous. In the context of this disclosure the term "non-continuous" or "not continuous" or equivalent expressions as applied to the one roll of the pair of yarn draw-off or withdrawal rolls, means that one such non-continuous roll is provided for each spinning apparatus or position. There is also provided a second friction spinning means which is arranged very near or in close proximity to the first friction spinning means but without touching the latter. Thus, there is formed a gap or nip of substantially constant but predeterminate width between the first and second friction spinning means.
The heretofore known devices for start spinning of a yarn employ a yarn end which is retracted from a bobbin and supplied, for performing the start spinning operation, to is started by infeeding fibers to the retracted yarn end at a reduced velocity of the friction spinning apparatus. It has also been proposed that prior to the start of spinning, in other words before the free floating fibers are fed to the inserted yarn end, the latter should be untwisted by movement of the friction spinning means in an opposite direction to enable better connection or interlacing of the delivered or infed fibers with the yarn end.
Such a device is known from the German Published Patent Application No. 3,318,687, in which a yarn end from a reverse rotated package is taken-up by a suction device and the yarn drawn-in by suction is retained by means of two lifting or reciprocating devices in the nip of two stationary friction spinning drums.
Before delivery of freely floating fibers to this yarn, the yarn is opened by reverse rotation of the friction spinning drums so that the fibers are in a substantially twist-free condition in the nip of the friction spinning drums. Thereafter, the friction spinning drums are placed into operation with reduced rotational speed in the normal direction or rotation and freely floating fibers are delivered to the opened yarn. The yarn which is thus produced, is withdrawn at a correspondingly reduced speed and delivered to a joining or connection means.
In order to take-up or handle the continuously delivered yarn during the time required for the joining or connection operation, the delivered yarn is received by a suction nozzle functioning as a yarn store or storage.
After completion of the joining or connection operation, the entire device is run-up or accelerated to the operating speed and thereafter is disconnected from the necessary auxiliary drive means and is driven by the normal drive means at the operating speed.
Certain of the disadvantages of a device of this type reside in the appreciable amount of auxiliary equipment needed for the start spinning operation. To overcome such drawbacks the herein named co-inventor, Emil Briner, devised along with a co-inventor Richard Hieronymi, a method for the start spinning of a yarn at a friction spinning device which could be accomplished in relatively uncomplicated fashion and through the use of relatively simple means.
The method according to such invention of Emil Briner and Richard Hieronymi has been disclosed in the aforementioned commonly assigned, U.S. Pat. No. 4,680,924, granted July 21, 1987, and in the cognate European Patent Application No. 86112564.9. As background, the invention of such U.S. Pat. No. 4,680,92, will be again disclosed herein with reference to FIGS. 1 to 7. When considering and describing FIGS. 1 to 7 of the instant disclosure, the same will be considered in an abbreviated form, in other words a description which does not include all of the reference characters appearing in the aforementioned U.S. Pat. No. 4,680,924, such being done merely to provide appropriate background information for understanding aspects and principles of the present development.
Even so, the method for performing a start spinning operation as described in the aforementioned U.S. Pat. No. 4,680,924, is afflicted with the shortcoming that there exists a certain unreliability in the engagement of the start of the yarn by the yarn draw-off or withdrawal means.